Anatomy and Physiology Answer Key

The ganglion cells respond by depolarization and

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Unformatted text preview: In dim light, the opposite happens; the pupil expands to allow more light into the eye. (b) Control of over the entry of light is appropriate as a reflex activity because the response is immediate and unconscious. In this way, the eye can be protected against damage and vision Biozone International 2009 Photocopying Prohibited 15 8. Each type of cone, blue, green and yellow-green (or red), responds maximally to one particular wavelength of light. The differential response of the cones to light is interpreted by the brain as color. metabolism. Examples: insulin and glucagon, parathormone (increases blood calcium) and calcitonin (lowers blood calcium). (b) In general principle, the product of a series of (hormone controlled) reactions controls its own production by turning off the pathway when it reaches a certain level. If there is too little of the product, its production is switched on again. Hearing (page 89) 1. 2. (a) Ear drum: Vibrates in response to sound waves. (b) Ear ossicles: Transmit the sound waves from the ear drum to the smaller oval window. (c) Oval window: Amplifies the sound waves before they enter the fluid filled inner ear (because of its smaller surface area). (d) Sensory hair cells: Respond to the stimulus of pressure waves in the fluid filled inner ear by generating electrical impulses. (e) Auditory nerve: Transmits the impulses from the sensory hair cells to the brain for processing. 2. Only the target cells have the appropriate receptors on the membrane to respond to the hormone. Other (nontarget) cells will not be affected. 3. (a) Hormones must circulate in the blood to reach the target cells and a metabolic response must be initiated. This takes some time. (b) Hormones bring about a metabolic change and often start a sequence of cascading, interrelated events. Once started, these events take time to conclude. Nervous responses continue only for the time that the stimulation continues. Sound waves are converted into pressure waves in the fluid. Because fluid is...
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This document was uploaded on 01/28/2014.

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